Rear End – Replacement of bump stops, spring seats, watts link bushings and axle pivot bushings
I positioned the floor jack just in front of the bracket for the trailing arm. After lifting the car I placed a jack stand as shown.
I was hoping that the positioning of the jack stand would allow me to drop the trailing arm brackets a little later on without having to reposition.
I removed the rear tires and set them out of the way. I took lots of pictures before further disassembly so I’d have an idea of what went where.
Jounce
Bumpers (aka Bump Stops)
Tools:
-Flat head screwdriver
-rotary tool (Dremel) with small sanding drum
-5/8” forstner bit (or same size drill bit, a drill press was helpful)
-4” 2-jaw heavy duty gear puller (this was about $15 at AutoZone, Ampro model T74163)
-ratchet with socket to drive the gear puller
-large socket (I used a 15/16”)
Process:
I grabbed the existing bump stop and used a screwdriver to help me pop them free from the tabs on the bump stop seat. I was pulling down on them as I pried, and a couple of tries popped them loose.
Skipping through some irrelevant frustration, here’s what I did next that worked.
Knowing that there is a 15mm bolt head up inside the bump stop seat, I took the new bump stops to the drill press and enlarged the hole with a 5/8” forstner bit. I placed the bump stop upside down for drilling as it helped locate the bit in the center of the existing hole and made it easy to hold onto as I drilled. I took an Exacto blade and trimmed up the rough top edge of the hole.
Those tabs punched into the bump stop seat were vexing. I ended up marking the top of the new bump stops and dremeling until I had 4 flat areas on the top lip that would clear the metal tabs.
Returning to the car, I setup the gear puller and prepared for a fight to get these seated properly. I learned the hard way to use the biggest socket I had that still fit inside the bump stop. Otherwise, the gear puller just pushed the socket into the hole at the top of the bump stop.
After worrying the bump stops into position and just before it seemed the gear puller would break free (again!), I stopped and pushed upward on the un-dremeled lip of the bump stop to make sure it had cleared the metal tabs.
Finally, I grabbed the bump stop and twisted until the un-dremeled lip was positioned above those metal tabs. I could have benefited from a strap wrench to do the turning.
Spring
Seats
Tools:
-metric socket set with BIG handled ratchet
-metric wrench set
-floor jack
-stack of scrap wood
-small wire brush
Process:
Continuing from the end of the bump stop replacement, I needed more clearance to remove the springs. I started by removing the bell crank bolt and nut.
The bell crank bolt was difficult to break loose. I don’t own any air tools. It felt far tighter than the 90 ft-lbs it is supposed to be torqued to.
Next I placed the floor jack under the rear axle under one of the springs. I lifted just a little and stuck some scrap wood under there, then set the axle down on the wood. I repeated this on the other side until the axle was resting on the wood.
I then backed out the bottom bolts on the shock absorbers. By using my free hand to hold the nut against the shock absorber as the bolt came out, I had an easier time wrestling the bolt out.
I removed the bolts holding the sway bar cushions against the backside of the axle and pulled the sway bar toward the rear of the car a little ways.
I put the floor jack back under the axle and lifted a little, then removed a few pieces of the scrap wood to allow the axle to droop a little more. I knew the axle was low enough when the springs looked like this:
The rubber spring seat lifted up with the spring a little in this picture, but you get the idea.
The bottom spring isolator (spring seat) is pretty flimsy. I ignored it as I worried the springs out. I pushed the bottom of the spring towards the front of the car, taking advantage of the axle droop to create a ramp out of the top of the spring seat.
Once the spring was pushed forward, I pushed it toward the center of the car and it popped loose.
I wire-brushed the spot where the spring seat sits, then installed the new spring seat. I put the other spring seat on top of the spring and positioned it. I had the bottom of the spring behind the bottom spring seat, and once again took advantage of the ramp to push the spring home. Once seated, I checked that the spring seats were in the proper locations. I don’t know if it mattered, but I turned the springs to approximately the same position they started out.
Watts
Linkage Bushings
Tools:
-metric socket set ratchet
-metric wrench set
-hacksaw with metal blade
-hammer and flat blade screwdriver
-pliers
-press and a bushing set
Process:
Continuing from the end of the spring seat replacement, I grabbed a socket and ratchet and backed out the bolts holding the bushings. The “top link” is the one on the right that connects at the top of the bell crank.
There is a nut on the top link only that has a flange. The flange will spin until it connects with the car, then it held still as I backed out the bolt. The other link just threads into the car; there is no nut. Once the link was out, I was careful not to exert force against the ball joints where the links connect to the bell crank. I didn’t want to break anything or cause any leaks in grease seals.
I pushed out the metal center piece on each bushing, then pushed out the rubber part of the bushing. This left a metal liner inside the watts link that needed to come out. I grabbed a hacksaw and carefully cut through the metal liner, turning the link to cut the flange in the liner out on one edge. I took a hammer and screwdriver and hammered on the outside of the liner, driving it toward the center of the link.
One of the links came out by hand, and the other came out with a pair of pliers. Now it was time to press in the replacement pieces.
I pressed each rubber piece into the link, then grabbed the grease and a Popsicle stick to apply it. I made sure to get grease in the little channels inside the new bushing. I then pressed in the metal piece until I had this:
I re-installed the watts link, noting that the bell crank has an indicator (“BACK UP”) to help orient the thing as the two ends are NOT interchangeable. I snugged the bolts down but did not torque them. They are supposed to be torqued to 60 ft-lb once the car is sitting on its wheels. I made a note to do this once the wheels were back on and I’d backed the car onto my ramps.
Axle
Pivot Bushing
Tools:
-metric socket set with ratchet
-metric wrench set
-torque wrench
-scratch awl
-press set
-strap wrench (or enormous pliers with a 2-5/8” jaw)
-stack of scrap wood
-floor jack
Process:
Continuing from the end of the watts linkage bushings replacement, I reattached the sway bar cushions and torqued them down to 40 ft-lb. I then put the bolts back in the shock absorbers and tightened them down to 50 ft-lb.
I took this picture of the side of the trailing arm. There are a number of small bolts and nuts that secure brake and e-brake lines, and I wanted to be sure I put them back where they belonged. I loosened these two, plus one more on the trailing arm bushing bracket and another that connects to the car body itself just inside the wheel well. I ended up with two nuts, a machine screw and a sheet metal screw from each side of the car. The idea here is to free the brake lines and the e-brake cable so they aren’t damaged when the trailing arms are pulled down.
I climbed under the car with a scratch awl and scratched the body where the trailing arm bracket meets the body. The scratches would help me line everything back up again later, though I’ll be asking for a full alignment from the pros when I’m all done.
I backed all four bracket bolts out of both sides of the car. I checked once more to make sure the freed brake lines wouldn’t be pushed around by the brackets once they started coming down. Next I put the floor jack under the backside of the axle in the middle of the car. By raising the back of the axle just a little, I was able to get the front ends of the trailing arms to droop revealing the bolt holding the bushing inside the bracket.
The bolt holding the bracket to the bushing is on pretty tight. I took a wrench and put it on the nut on the back side of the bracket, then set some scrap wood under the trailing arm to keep the trailing arm from drooping too much as I wrenched and to keep the wrench behind the nut from spinning. I then put a ratchet on the bolt on the front of the bracket and hauled on it until it broke loose. Once the bolt was out, the bracket came off of the bushing pretty easily. I just pushed up and forward on the bracket and it came right off. Here’s the bushing in all of its glory.
That’s the bushing with the metal insert. The rubber part of the bushing “mushrooms” over the edge of the trailing arm opening a little.
And here’s the bracket:
I headed to the auto parts store and borrowed a press set from them. The set was actually a u-joint set but it had all the pieces I needed.
I set it up like this.
The receiving cup has to be at least 2-5/8” in inner diameter, and about 3” deep. There’s a cutout in the cup that meant I didn’t have to wrestle the trailing arm down any further than I showed in an earlier picture.
This next part worked better with an extra set of hands to help. I had my helper hold the receiving cup and the “c-clamp” piece in place on the outside of the bushing. I positioned the screw and used a socket and ratchet to drive it in. That screw used a socket I didn’t have, and I had to make a return trip to the parts store to pick one up.
The screw pushed the bushing into the bottom of the receiving cup before the bushing was completely free. I removed the tools and grabbed the part of the bushing that was sticking out with a strap wrench and pulled it the rest of the way out. If I had a huge set of pliers I could have used those.
I used a Popsicle stick to put grease inside the new bushings, making sure to get the grease into the channels inside the bushing. I was able to push the metal inserts into the bushing by hand. I cleaned off the excess grease and did this with the press set:
The piece on the left end of the “c-clamp” is just a piece that would sit on the outside edge of the trailing arm without marring it. The bushing has a 3/8” ratchet extension pushed through it to help me hold the bushing tool in line with the bushing. The extension fits through the hole at the bottom of the c-clamp, too. The bushing tool could have been replaced with a good-sized steel washer for this effort.
A second set of hands helped me get everything in place. The screw pushed the bushing part way in until it hit the bottom of the c-clamp. I disassembled the setup and put the original receiving cup back on the bottom of the c-clamp. I had to set and re-set the screw on the inside of the bushing so the bushing would push evenly into the trailing arm. I knew I was done when the “mushroom” edge of the new bushing was sticking out of both sides.
The metal bushing insert was off-center after all that pressing, so I went back and used a regular c-clamp to re-center it.
I put the bracket back over the bushing and tightened down the bolt to 80 ft-lb.
After one more look at the brake cable and lines, I lowered the floor jack and the brackets rose up to meet the body. I started all four bolts in both brackets but did not tighten them yet.
Once all of the bolts were almost all the way in, I summoned a helper. Careful positioning of the brackets is necessary, and I had the helper move the axle back and forth and the trailing arm in and out as needed in order to perfectly align the bracket. Then I drove the bolts home and torqued them to 40 ft-lb. Even with this care, I still plan to ask for a 4-wheel alignment at the shop, and to confess that I had the trailing arms loose so they take me seriously.
I tracked down all of the brake line brackets and tightened them by hand, ignoring the recommendation of 100 in-lb.
I put the bell crank bolt back in and torqued the nut to 90 ft-lb.
I put the wheels back on (100 ft-lb on those lug nuts), lowered the car, and backed it onto my ramps. I climbed back under and torqued the watts link bushing bolts to 60 ft-lb.
That was it for the rear end! I spent about 10 hours on this, not counting the shopping trips for tools and time spent puzzling out how to perform these steps.